1. Field of the Invention
This invention relates to a process for making fried snack products from mixtures of precooked and raw flours made from cereal grains such as corn, wheat, oats, rye, barley, rice, and the like. One practice of the invention is particularly suitable for making extruded snack products from dry milled corn flours.
2. Description of the Prior Art
Traditional fried corn snacks are made from whole kernel corn principally by two methods. Kernels of corn are steeped in a hot lime solution to soften the outer hull and partially gelatinize the starch in the endosperm. The treated grains are washed to remove the softened hull and ground to form a plastic dough containing about 50% moisture, known as masa. In one method, thin pieces of masa dough are formed by extrusion and fall directly into hot cooking oil in a deep fat fryer, as described in U.S. Pat. Nos. 2,002,053 to Doolin; 3,083,103 to Anderson et al; and 3,278,311 to Brown et al. As a result of the high initial moisture content of the dough pieces, the fat content of the fried product is undesirably high, often above 35% to 40%. The fried products also are hard and brittle.
In another method, a similar freshly-ground masa is sheeted between rollers, cut into pieces, and baked to reduce the moisture content from about 35% to as low as about 20% before frying, as described in U.S. Pat. Nos. 2,905,559 to Anderson et al and 3,690,895 to Amadon et al. The dough should have a moisture content of about 50% for effective sheeting, but frying a sheeted corn-based dough with 50% moisture typically causes undesirable puffing of the fried product. As a result of the reduced moisture content of the baked dough pieces, the fat content of the fried product is about 20% to 25%. However, the fried pieces tend to have an uneven expansion, with large blistered areas and a hard, chewy texture. The same uneven structure also is found in the extruded masa-based snacks described above.
It appears that areas of non-uniform structure in the fried masa-based snacks may be caused by non-uniform composition of the masa dough, namely, areas of undercooked corn particles, resulting in non-expanded sections of the fried snack.
All such conventional corn snacks have the characteristic flavor of lime-soaked corn as a result of residual lime and the by-products from its reaction with corn constituents.
Dried masa flour is also available for the manufacture of corn snacks and other Mexican food specialties, such as tortillas and taco shells. In typical processes for making such dried masa flour, described in U.S. Pat. Nos. 4,344,366 to Garza; 2,704,257 to Diez De Sollano et al; and 3,369,908 to Gonzales et al, the lime-treated corn is ground and dehydrated to a stable form. The dried masa flour can be later rehydrated with water to form a dough for extrusion or sheeting.
Partially cooked, dry-milled whole corn flours are also made from whole corn kernels, as in the methods described in U.S. Pat. Nos. 3,404,986 to Wimmer et al and 4,089,259 to Stickle et al. The corn in these methods is gelatinized without lime treatment, i.e., without removing the outer hull. These whole corn flours can be mixed with water to form a dough for making a fried snack. However, the fried snacks made from these whole corn flours are hard and brittle and retain too much fat, probably because of the low water absorption of the flours. The same is true for other cereal grains, which otherwise have potential for use as novel, nutritious, economical fried snack products. Such cereal grains include precooked wheat, known as bulgur, steam-rolled grains, such as oats and rye, precooked barley, and rice. These cereal grains can be milled into flours and mixed with water to form a dough. However, dough pieces made from such grains do not expand when fried to form a desirable porous texture; but instead they form a non-porous, flinty product that is undesirable as a snack food.
It would be desirable to produce fried snacks from mixtures of dry cereal ingredients not normally used for snack foods to form fried snack products which are well expanded with uniform porosity, are not brittle and have acceptable fat content. It would be particularly desirable to produce corn snacks and other cereal grain snacks that can be extruded and fried at moisture levels above 40%, while avoiding intermediate treatment, such as moisture content reduction before frying. It would also be desirable to produce an extruded fried corn snack with a characteristic full corn flavor from a variety of non-lime-treated dry corn products. The prior art has not suggested how to produce a corn-based fried snack with uniform porosity and expansion and reasonably low fat content. To produce fried snacks from corn processed by dry-milling avoids the more cumbersome and time-consuming process of preparing freshly-ground masa. It also can eliminate the stream pollution and the costly waste treatment facilities required when making snacks from lime-treated corn kernels.
The method of this invention provides extruded fried corn snacks that overcome the problems described above. In addition, the method provides novel fried snack products made from cereal grains and flours heretofore not used for commercial snack foods.